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Song Z, Kalyani M, Becker JB. Sex differences in motivated behaviors in animal models. Curr Opin Behav Sci 2018; 23:98-102. [PMID: 30467551 DOI: 10.1016/j.cobeha.2018.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Sex differences exist in the motivation for sexual behavior, food, parental care and motivation to take drugs. There are also sex differences in the likelihood of exhibiting motivational disorders such as anhedonia, depression, addictive behavior, and eating disorders. This brief review summaries recent studies on sex differences in all motivated behaviors in social and non-social contexts, focusing on animal models. We also discuss the roles of gonadal hormones and the nonapeptides (nine amino acid peptides) in modulating sex differences in motivation. We propose that sex differences in the neural mechanisms mediating endogenous motivation for food, sex, partners and care of offspring underlie sex differences in all motivated behaviors.
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Affiliation(s)
- Zhimin Song
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109
| | - Manu Kalyani
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109
| | - Jill B Becker
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109.,Department of Psychology, University of Michigan, Ann Arbor, MI 48109
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52
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Everett NA, McGregor IS, Baracz SJ, Cornish JL. The role of the vasopressin V1A receptor in oxytocin modulation of methamphetamine primed reinstatement. Neuropharmacology 2018; 133:1-11. [DOI: 10.1016/j.neuropharm.2017.12.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/11/2017] [Accepted: 12/20/2017] [Indexed: 12/17/2022]
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53
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Xiao L, Priest MF, Kozorovitskiy Y. Oxytocin functions as a spatiotemporal filter for excitatory synaptic inputs to VTA dopamine neurons. eLife 2018; 7:33892. [PMID: 29676731 PMCID: PMC5910020 DOI: 10.7554/elife.33892] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/26/2018] [Indexed: 01/15/2023] Open
Abstract
The experience of rewarding or aversive stimuli is encoded by distinct afferents to dopamine (DA) neurons of the ventral tegmental area (VTA). Several neuromodulatory systems including oxytocin regulate DA neuron excitability and synaptic transmission that process socially meaningful stimuli. We and others have recently characterized oxytocinergic modulation of activity in mouse VTA DA neurons, but the mechanisms underlying oxytocinergic modulation of synaptic transmission in DA neurons remain poorly understood. Here, we find that oxytocin application or optogenetic release decrease excitatory synaptic transmission, via long lasting, presynaptic, endocannabinoid-dependent mechanisms. Oxytocin modulation of excitatory transmission alters the magnitude of short and long-term depression. We find that only some glutamatergic projections to DA neurons express CB1 receptors. Optogenetic stimulation of three major VTA inputs demonstrates that oxytocin modulation is limited to projections that show evidence of CB1R transcripts. Thus, oxytocin gates information flow into reward circuits in a temporally selective and pathway-specific manner. The mammalian brain contains millions of nerve cells or neurons that communicate with each other via a process called neurotransmission. To send a message to its neighbor, a neuron releases a chemical called a neurotransmitter into the space between the cells. The neurotransmitter then binds to receiver proteins on the target cell. Another group of chemicals, known as neuromodulators, regulate this process, adjusting the way that neurons respond to neurotransmitters. In doing so, they help regulate many types of behavior in mammals. The neuromodulator oxytocin, for example, has earned the nickname ‘the love hormone’ because it promotes social behavior and bonding. It does this in part by altering the activity of neurons in a brain region called the ventral tegmental area (VTA). These neurons produce the brain’s main reward signal, dopamine, which is itself a neuromodulator. But exactly how oxytocin affects the activity of dopamine-producing neurons is unclear. By recording from individual neurons in slices of mouse brain tissue, Xiao et al. show that oxytocin filters inputs to dopamine neurons in the VTA. It does this by making the dopamine neurons release another group of reward signals, known as endocannabinoids. These are the brain’s own version of the chemicals found inside cannabis plants. The endocannabinoids bind to neurons that provide input to the VTA dopamine neurons. Some of these input neurons normally activate the VTA by releasing a neurotransmitter called glutamate. However, the binding of endocannabinoids decreases their ability to do this, and thereby lowers the activation of the VTA dopamine neurons. But not all glutamate neurons are sensitive to endocannabinoids. Moreover, oxytocin affects glutamate neurons that fire repeatedly less than it affects those that fire only occasionally. Oxytocin thus acts as a filter. It allows certain inputs – those that are repeatedly active and those that are insensitive to endocannabinoids – to continue activating VTA dopamine neurons. At the same time, it weakens the influence of other inputs. Dopamine release in the VTA drives drug abuse and addiction. Understanding how oxytocin affects VTA neurons may thus open up new avenues for the treatment of addiction disorders.
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Affiliation(s)
- Lei Xiao
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Michael F Priest
- Department of Neurobiology, Northwestern University, Evanston, United States
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Skinner JA, Garg ML, Dayas CV, Fenton S, Burrows TL. Relationship between dietary intake and behaviors with oxytocin: a systematic review of studies in adults. Nutr Rev 2018. [DOI: 10.1093/nutrit/nux078] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Janelle A Skinner
- Nutrition and Dietetics School of Health Sciences, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia
- Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, New South Wales, Australia
| | - Manohar L Garg
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia
| | - Christopher V Dayas
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia
| | - Sasha Fenton
- Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, New South Wales, Australia
| | - Tracy L Burrows
- Nutrition and Dietetics School of Health Sciences, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia
- Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, New South Wales, Australia
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55
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Leslie M, Silva P, Paloyelis Y, Blevins J, Treasure J. A Systematic Review and Quantitative Meta-Analysis of Oxytocin's Effects on Feeding. J Neuroendocrinol 2018; 30:10.1111/jne.12584. [PMID: 29480934 PMCID: PMC6292740 DOI: 10.1111/jne.12584] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/20/2018] [Indexed: 12/15/2022]
Abstract
PURPOSE Oxytocin's anorexigenic effects have been widely documented and accepted; however, no paper has yet used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to compile previous findings in a single systematic review and quantitative meta-analysis. The current paper aimed to identify published and unpublished studies examining the effects of oxytocin on energy intake in animals and humans, and the factors that moderate this effect. METHODS Web of Science, Pub Med, and Ovid were searched for published and unpublished studies reporting the effects of oxytocin on energy intake in wild-type animals and in humans, when administered in the absence of other active drugs or surgery. RESULTS 2049 articles were identified through the original systematic literature search, from which 54 articles were identified as relevant for inclusion in this review. An additional 3 relevant articles were identified in a later update of the literature search. Overall, a single-dose of oxytocin was found to reduce feeding in animals. Despite several individual studies which found that this effect persists to the end of the third week of chronic administration in rodent models, overall, this anorexigenic effect did not hold in the meta-analyses testing the effects of chronic administration. There was no overall effect of oxytocin on energy intake in humans, although a trend was identified for oxytocin to reduce consumption of solid foods. CONCLUSIONS Oxytocin reduces energy intake when administered as a single dose. Oxytocin can inhibit feeding over two- to three-week periods in rodent models. These effects typically do not persist beyond the third week of treatment. The anorexigenic effect of oxytocin is moderated by pregnant status, dose, method of administration, and diet composition. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Monica Leslie
- Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London (KCL), London, UK
| | - Paulo Silva
- Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London (KCL), London, UK
| | - Yannis Paloyelis
- Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London (KCL), London, UK
| | - James Blevins
- Department of Veterans Affairs Medical Center, Office of Research and Development Medical Research Service, VA Puget Sound Health Care System, Seattle, WA, USA
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Janet Treasure
- Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London (KCL), London, UK
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Gartner SN, Aidney F, Klockars A, Prosser C, Carpenter EA, Isgrove K, Levine AS, Olszewski PK. Intragastric preloads of l-tryptophan reduce ingestive behavior via oxytocinergic neural mechanisms in male mice. Appetite 2018; 125:278-286. [PMID: 29471071 DOI: 10.1016/j.appet.2018.02.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/09/2018] [Accepted: 02/15/2018] [Indexed: 11/29/2022]
Abstract
Human and laboratory animal studies suggest that dietary supplementation of a free essential amino acid, l-tryptophan (TRP), reduces food intake. It is unclear whether an acute gastric preload of TRP decreases consumption and whether central mechanisms underlie TRP-driven hypophagia. We examined the effect of TRP administered via intragastric gavage on energy- and palatability-induced feeding in mice. We sought to identify central mechanisms through which TRP suppresses appetite. Effects of TRP on consumption of energy-dense and energy-dilute tastants were established in mice stimulated to eat by energy deprivation or palatability. A conditioned taste aversion (CTA) paradigm was used to assess whether hypophagia is unrelated to sickness. c-Fos immunohistochemistry was employed to detect TRP-induced activation of feeding-related brain sites and of oxytocin (OT) neurons, a crucial component of satiety circuits. Also, expression of OT mRNA was assessed with real-time PCR. The functional importance of OT in mediating TRP-driven hypophagia was substantiated by showing the ability of OT receptor blockade to abolish TRP-induced decrease in feeding. TRP reduced intake of energy-dense standard chow in deprived animals and energy-dense palatable chow in sated mice. Anorexigenic doses of TRP did not cause a CTA. TRP failed to affect intake of palatable yet calorie-dilute or noncaloric solutions (10% sucrose, 4.1% Intralipid or 0.1% saccharin) even for TRP doses that decreased water intake in thirsty mice. Fos analysis revealed that TRP increases activation of several key feeding-related brain areas, especially in the brain stem and hypothalamus. TRP activated hypothalamic OT neurons and increased OT mRNA levels, whereas pretreatment with an OT antagonist abolished TRP-driven hypophagia. We conclude that intragastric TRP decreases food and water intake, and TRP-induced hypophagia is partially mediated via central circuits that encompass OT.
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Affiliation(s)
| | | | | | - Colin Prosser
- Dairy Goat Co-operative (NZ) Ltd, Hamilton, New Zealand
| | | | | | - Allen S Levine
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Pawel K Olszewski
- University of Waikato, Hamilton, New Zealand; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA.
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57
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Plessow F, Marengi DA, Perry SK, Felicione JM, Franklin R, Holmes TM, Holsen LM, Makris N, Deckersbach T, Lawson EA. Effects of Intranasal Oxytocin on the Blood Oxygenation Level-Dependent Signal in Food Motivation and Cognitive Control Pathways in Overweight and Obese Men. Neuropsychopharmacology 2018; 43:638-645. [PMID: 28930284 PMCID: PMC5770767 DOI: 10.1038/npp.2017.226] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 08/29/2017] [Accepted: 09/15/2017] [Indexed: 01/08/2023]
Abstract
Recent research indicates that the hypothalamic neuropeptide hormone oxytocin is a key central nervous system factor in the regulation of food intake and weight. However, the mechanisms underlying the anorexigenic effects of oxytocin in humans are unknown and critical to study to consider oxytocin as a neurohormonal weight loss treatment. We performed a randomized, double-blind, placebo-controlled crossover study with single-dose intranasal oxytocin (24 IU) in ten overweight or obese, otherwise healthy men. Following oxytocin/placebo administration, participants completed an established functional magnetic resonance imaging food motivation paradigm. We hypothesized that oxytocin would reduce the blood oxygenation level-dependent (BOLD) signal to high-calorie food vs non-food visual stimuli in the ventral tegmental area (VTA), the origin of the mesolimbic dopaminergic reward system. Following oxytocin administration, compared to placebo, participants showed bilateral VTA hypoactivation to high-calorie food stimuli. A secondary exploratory whole-brain analysis revealed hypoactivation in additional hedonic (orbitofrontal cortex, insula, globus pallidus, putamen, hippocampus, and amygdala) and homeostatic (hypothalamus) food motivation and hyperactivation in cognitive control (anterior cingulate and frontopolar cortex) brain regions following oxytocin administration vs placebo. Oxytocin administration reduces the BOLD signal in reward-related food motivation brain regions, providing a potential neurobiological mechanism for the anorexigenic oxytocin effects in humans. Furthermore, our data indicate that oxytocin administration reduces activation in homeostatic and increases activation in cognitive control brain regions critically involved in regulating food intake and resolving affective conflict, respectively. Future studies are required to link these changes in brain activation to oxytocin effects on food intake and weight.
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Affiliation(s)
- Franziska Plessow
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, USA,Department of Medicine, Harvard Medical School, Boston, MA, USA,Neuroendocrine Unit, Massachusetts General Hospital, 55 Fruit Street BUL457B, Boston, MA 02114, USA. Tel: +1-617-726-0784; Fax: +1-617-726-5072; E-mail:
| | - Dean A Marengi
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Sylvia K Perry
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, USA
| | - Julia M Felicione
- Division of Neurotherapeutics, Massachusetts General Hospital, Charlestown, MA, USA
| | - Rachel Franklin
- Division of Neurotherapeutics, Massachusetts General Hospital, Charlestown, MA, USA
| | - Tara M Holmes
- Clinical Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Laura M Holsen
- Division of Women’s Health, Department of Medicine and Department of Psychiatry, Brigham and Women’s Hospital, Boston, MA, USA,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Nikolaos Makris
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA,Center for Morphometric Analysis, Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA
| | - Thilo Deckersbach
- Division of Neurotherapeutics, Massachusetts General Hospital, Charlestown, MA, USA,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Elizabeth A Lawson
- Neuroendocrine Unit, Massachusetts General Hospital, Boston, MA, USA,Department of Medicine, Harvard Medical School, Boston, MA, USA
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58
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Duque-Wilckens N, Steinman MQ, Busnelli M, Chini B, Yokoyama S, Pham M, Laredo SA, Hao R, Perkeybile AM, Minie VA, Tan PB, Bales KL, Trainor BC. Oxytocin Receptors in the Anteromedial Bed Nucleus of the Stria Terminalis Promote Stress-Induced Social Avoidance in Female California Mice. Biol Psychiatry 2018; 83:203-213. [PMID: 29066224 PMCID: PMC5743604 DOI: 10.1016/j.biopsych.2017.08.024] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/16/2017] [Accepted: 08/29/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND The neuropeptide oxytocin (OT) is a key regulator of social and emotional behaviors. The effects of OT are context dependent, and it has been proposed that OT increases the salience of both positive and negative social cues. Here we tested whether the bed nucleus of the stria terminalis (BNST) mediates anxiogenic effects of OT. METHODS First, we studied the effects of systemic administration of an OT receptor (OTR) antagonist L-368,899 on social behavior in male and female California mice exposed to social defeat. We examined the effect of L-368,899 on G protein activation and used early growth response factor 1 immunohistochemistry to identify potential sites of OTR action. Finally, we examined the effects of L-368,899 infused in the BNST on behavior. RESULTS A single dose of systemic L-368,899 increased social approach in stressed female mice and decreased social approach in male mice naïve to defeat. L-368,899 prevented OT activation of G proteins and did not activate G proteins in the absence of OT. Intranasal OT, which reduces social approach in female mice but not male mice, increased early growth response factor 1 immunoreactivity in the nucleus accumbens core and anteromedial BNST in female mice but not in male mice. Stressed female mice that received an infusion of L-368,899 into the anteromedial BNST but not the nucleus accumbens core increased social approach and decreased social vigilance responses. CONCLUSIONS Our results suggest that OTR activation in anteromedial BNST induces a vigilance response in which individuals avoid, yet attend to, unfamiliar social contexts. Our results suggest that OTR antagonists may have unappreciated therapeutic potential for stress-induced psychiatric disorders.
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Affiliation(s)
| | - Michael Q Steinman
- Molecular, Cellular, and Integrative Physiology Graduate Group, University of California, Davis, Davis, California
| | - Marta Busnelli
- Institute of Neuroscience, National Research Council, Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano Milan, and Humanitas Clinical and Research Center, Rozzano, Italy
| | - Bice Chini
- Institute of Neuroscience, National Research Council, Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano Milan, and Humanitas Clinical and Research Center, Rozzano, Italy
| | - Sae Yokoyama
- Psychology Department, University of California, Davis, Davis, California
| | - Mary Pham
- Psychology Department, University of California, Davis, Davis, California
| | - Sarah A Laredo
- Animal Behavior Graduate Group, University of California, Davis, Davis, California
| | - Rebecca Hao
- Psychology Department, University of California, Davis, Davis, California
| | | | - Vanessa A Minie
- Psychology Department, University of California, Davis, Davis, California
| | - Phillip B Tan
- Psychology Department, University of California, Davis, Davis, California
| | - Karen L Bales
- Psychology Department, University of California, Davis, Davis, California
| | - Brian C Trainor
- Animal Behavior Graduate Group, University of California, Davis, Davis, California; Psychology Department, University of California, Davis, Davis, California.
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Maejima Y, Yokota S, Nishimori K, Shimomura K. The Anorexigenic Neural Pathways of Oxytocin and Their Clinical Implication. Neuroendocrinology 2018; 107:91-104. [PMID: 29660735 DOI: 10.1159/000489263] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 04/15/2018] [Indexed: 12/21/2022]
Abstract
Oxytocin was discovered in 1906 as a peptide that promotes delivery and milk ejection; however, its additional physiological functions were determined 100 years later. Many recent articles have reported newly discovered effects of oxytocin on social communication, bonding, reward-related behavior, adipose tissue, and muscle and food intake regulation. Because oxytocin neurons project to various regions in the brain that contribute to both feeding reward (hedonic feeding) and the regulation of energy balance (homeostatic feeding), the mechanisms of oxytocin on food intake regulation are complicated and largely unknown. Oxytocin neurons in the paraventricular nucleus (PVN) receive neural projections from the arcuate nucleus (ARC), which is an important center for feeding regulation. On the other hand, these neurons in the PVN and supraoptic nucleus project to the ARC. PVN oxytocin neurons also project to the brain stem and the reward-related limbic system. In addition to this, oxytocin induces lipolysis and decreases fat mass. However, these effects in feeding and adipose tissue are known to be dependent on body weight (BW). Oxytocin treatment is more effective in food intake regulation and fat mass decline for individuals with leptin resistance and higher BW, but is known to be less effective in individuals with normal BW. In this review, we present in detail the recent findings on the physiological role of oxytocin in feeding regulation and the anorexigenic neural pathway of oxytocin neurons, as well as the advantage of oxytocin usage for anti-obesity treatment.
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Affiliation(s)
- Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Shoko Yokota
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Katsuhiko Nishimori
- Department of Molecular and Cell Biology, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
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60
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Abstract
Oxytocin, a hypothalamic hormone that is secreted directly into the brain and enters the peripheral circulation through the posterior pituitary gland, regulates a range of physiologic processes, including eating behaviour and metabolism. In rodents and nonhuman primates, chronic oxytocin administration leads to sustained weight reduction by reducing food intake, increasing energy expenditure and inducing lipolysis. Oxytocin might improve glucose homeostasis, independently of its effects on weight. Clinical studies are beginning to translate these important preclinical findings to humans. This Review describes key data linking oxytocin to eating behaviour and metabolism in humans. For example, a single intranasal dose of oxytocin can reduce caloric intake, increase fat oxidation and improve insulin sensitivity in men. Furthermore, a pilot study of 8 weeks of oxytocin treatment in adults with obesity or overweight led to substantial weight loss. Together, these data support further investigation of interventions that target pathways involving oxytocin as potential therapeutics in metabolic disorders, including obesity and diabetes mellitus. Therapeutic considerations and areas for further research are also discussed.
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Affiliation(s)
- Elizabeth A Lawson
- Neuroendocrine Unit, Massachusetts General Hospital, 55 Fruit Street, Bulfinch 457 D, Boston, Massachusetts 02114, USA
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61
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Klockars OA, Waas JR, Klockars A, Levine AS, Olszewski PK. Neural Basis of Ventromedial Hypothalamic Oxytocin-Driven Decrease in Appetite. Neuroscience 2017; 366:54-61. [DOI: 10.1016/j.neuroscience.2017.10.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 02/03/2023]
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62
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Sasaki T. Neural and Molecular Mechanisms Involved in Controlling the Quality of Feeding Behavior: Diet Selection and Feeding Patterns. Nutrients 2017; 9:nu9101151. [PMID: 29053636 PMCID: PMC5691767 DOI: 10.3390/nu9101151] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/12/2017] [Accepted: 10/13/2017] [Indexed: 12/20/2022] Open
Abstract
We are what we eat. There are three aspects of feeding: what, when, and how much. These aspects represent the quantity (how much) and quality (what and when) of feeding. The quantitative aspect of feeding has been studied extensively, because weight is primarily determined by the balance between caloric intake and expenditure. In contrast, less is known about the mechanisms that regulate the qualitative aspects of feeding, although they also significantly impact the control of weight and health. However, two aspects of feeding quality relevant to weight loss and weight regain are discussed in this review: macronutrient-based diet selection (what) and feeding pattern (when). This review covers the importance of these two factors in controlling weight and health, and the central mechanisms that regulate them. The relatively limited and fragmented knowledge on these topics indicates that we lack an integrated understanding of the qualitative aspects of feeding behavior. To promote better understanding of weight control, research efforts must focus more on the mechanisms that control the quality and quantity of feeding behavior. This understanding will contribute to improving dietary interventions for achieving weight control and for preventing weight regain following weight loss.
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Affiliation(s)
- Tsutomu Sasaki
- Laboratory for Metabolic Signaling, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan.
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63
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Ong ZY, Bongiorno DM, Hernando MA, Grill HJ. Effects of Endogenous Oxytocin Receptor Signaling in Nucleus Tractus Solitarius on Satiation-Mediated Feeding and Thermogenic Control in Male Rats. Endocrinology 2017; 158:2826-2836. [PMID: 28575174 PMCID: PMC5659667 DOI: 10.1210/en.2017-00200] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/24/2017] [Indexed: 12/15/2022]
Abstract
Central oxytocin receptor (OT-R) signaling reduces food intake and increases energy expenditure, but the central sites and mechanisms mediating these effects are unresolved. We showed previously that pharmacological activation of OT-R in hindbrain/nucleus tractus solitarius (NTS) amplifies the intake-inhibitory effects of gastrointestinal (GI) satiation signals. Unexplored were the energetic effects of hindbrain OT-R agonism and the physiological relevance of NTS OT-R signaling on food intake and energy expenditure control. Using a virally mediated OT-R knockdown (KD) strategy and a range of behavioral paradigms, this study examined the role of endogenous NTS OT-R signaling on satiation-mediated food intake inhibition and thermogenic control. Results showed that, compared with controls, NTS OT-R KD rats consumed larger meals, were less responsive to the intake-inhibitory effects of a self-ingested preload, and consumed more chow following a 24-hour fast. These data indicate that NTS OT-R signaling is necessary for normal satiation control. Whereas both control and NTS OT-R KD rats increased core temperature following high-fat diet maintenance (relative to chow maintenance), the percent increase in core temperature was greater in control compared with NTS OT-R KD rats during the light cycle. Hindbrain oxytocin agonist delivery increased core temperature in both control and NTS OT-R KD rats and the percent increase relative to vehicle treatment was not significantly different between groups. Together, data reveal a critical role for endogenous NTS OT-R signaling in mediating the intake-inhibitory effects of endogenous GI satiation signals and in diet-induced thermogenesis.
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Affiliation(s)
- Zhi Yi Ong
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Diana M. Bongiorno
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Mary Ann Hernando
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Harvey J. Grill
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Klockars A, Brunton C, Li L, Levine AS, Olszewski PK. Intravenous administration of oxytocin in rats acutely decreases deprivation-induced chow intake, but it fails to affect consumption of palatable solutions. Peptides 2017; 93:13-19. [PMID: 28460894 DOI: 10.1016/j.peptides.2017.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 04/22/2017] [Accepted: 04/27/2017] [Indexed: 01/03/2023]
Abstract
Despite its limited ability to cross the blood-brain barrier, peripherally administered oxytocin (OT) acutely decreases food intake, most likely via the brainstem and hypothalamic mechanisms. Studies performed to date have focused mainly on the effects of subcutaneous or intraperitoneal OT on the consumption of only solid calorie-dense diets (either standard or high-fat), whereas it is unknown whether, similarly to central OT, peripherally administered peptide reduces intake of calorie-dilute and non-caloric palatable solutions. In this project, we established that 0.1μg/kg intravenous (IV) OT is the lowest anorexigenic dose, decreasing deprivation-induced standard chow intake by ca. 40% in rats and its effect does not stem from aversion. We then used this dose in paradigms in which effects of centrally acting OT ligands on consumption of palatable solutions had been previously reported. We found that IV OT did not change episodic intake of individually presented palatable solutions containing 10% sucrose, 0.1% saccharin, combined 10% sucrose-0.1% saccharin or 4.1%. Intralipid and it failed to affect daily scheduled consumption of a sucrose solution in non-deprived rats. In a two-bottle choice test, IV OT did not shift animals' preference from sucrose to Intralipid. Finally, OT injected IV prior to the simultaneous presentation chow and a sucrose solution in food-deprived rats significantly decreased chow intake, whereas sugar water consumption remained unchanged. We conclude that IV OT reduces deprivation-induced chow intake without causing aversion, but the dose effective in decreasing energy-driven consumption of high-calorie food fails to affect consumption of palatable calorie-dilute solutions.
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Affiliation(s)
- Anica Klockars
- Department of Biological Sciences, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | - Chloe Brunton
- Department of Biological Sciences, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | - Lu Li
- University of Auckland, Waikato Clinical School, Hamilton, 3240 New Zealand
| | - Allen S Levine
- Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA
| | - Pawel K Olszewski
- Department of Biological Sciences, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand; Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA.
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65
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Hume C, Sabatier N, Menzies J. High-Sugar, but Not High-Fat, Food Activates Supraoptic Nucleus Neurons in the Male Rat. Endocrinology 2017; 158:2200-2211. [PMID: 28430937 DOI: 10.1210/en.2016-1640] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 04/14/2017] [Indexed: 02/05/2023]
Abstract
Oxytocin is a potent anorexigen and is believed to have a role in satiety signaling. We developed rat models to study the activity of oxytocin neurons in response to voluntary consumption or oral gavage of foods using c-Fos immunohistochemistry and in vivo electrophysiology. Using c-Fos expression as an indirect marker of neural activation, we showed that the percentage of magnocellular oxytocin neurons expressing c-Fos increased with voluntary consumption of sweetened condensed milk (SCM). To model the effect of food in the stomach, we gavaged anesthetized rats with SCM. The percentage of supraoptic nucleus and paraventricular nucleus magnocellular oxytocin-immunoreactive neurons expressing c-Fos increased with SCM gavage but not with gastric distention. To further examine the activity of the supraoptic nucleus, we made in vivo electrophysiological recordings from SON neurons, where anesthetized rats were gavaged with SCM or single cream. Pharmacologically identified oxytocin neurons responded to SCM gavage with a linear, proportional, and sustained increase in firing rate, but cream gavage resulted in a transient reduction in firing rate. Blood glucose increased after SCM gavage but not cream gavage. Plasma osmolarity and plasma sodium were unchanged throughout. We show that in response to high-sugar, but not high-fat, food in the stomach, there is an increase in the activity of oxytocin neurons. This does not appear to be a consequence of stomach distention or changes in osmotic pressure. Our data suggest that the presence of specific foods with different macronutrient profiles in the stomach differentially regulates the activity of oxytocin neurons.
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Affiliation(s)
- Catherine Hume
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Nancy Sabatier
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - John Menzies
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
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66
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Xiao L, Priest MF, Nasenbeny J, Lu T, Kozorovitskiy Y. Biased Oxytocinergic Modulation of Midbrain Dopamine Systems. Neuron 2017; 95:368-384.e5. [PMID: 28669546 DOI: 10.1016/j.neuron.2017.06.003] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/03/2017] [Accepted: 05/26/2017] [Indexed: 01/08/2023]
Abstract
The release of dopamine (DA) regulates rewarding behavior and motor actions through striatum-targeting efferents from ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Here, we map and functionally characterize axonal projections from oxytocin neurons in the hypothalamic paraventricular nucleus to midbrain DA regions. Electrophysiological recordings of DA neurons reveal that both the application of oxytocin and optogenetic stimulation of oxytocinergic terminals suffice to increase DA neuron activity in the VTA but downregulate it in SNc. This biased modulation is mediated by oxytocin and vasopressin G-protein-coupled receptors. Oxytocin release directly activates DA neurons and indirectly inhibits them through local GABA neurons, but the relative magnitudes of the two mechanisms differ in VTA and SNc. Oxytocin-modulated DA neurons give rise to canonical striatal projections. Since hypothalamic oxytocinergic projections also target the striatum, oxytocin is poised to bias the balance of DA tone through multiple sites in vertebrate reward circuits.
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Affiliation(s)
- Lei Xiao
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Michael F Priest
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Jordan Nasenbeny
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Ting Lu
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208, USA
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67
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King CE, Griffin WC, Luderman LN, Kates MM, McGinty JF, Becker HC. Oxytocin Reduces Ethanol Self-Administration in Mice. Alcohol Clin Exp Res 2017; 41:955-964. [PMID: 28212464 PMCID: PMC5404956 DOI: 10.1111/acer.13359] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 02/14/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Excessive ethanol (EtOH) consumption remains an important health concern and effective treatments are lacking. The central oxytocin system has emerged as a potentially important therapeutic target for alcohol and drug addiction. These studies tested the hypothesis that oxytocin reduces EtOH consumption. METHODS Male C57BL/6J mice were given access to EtOH (20% v/v) using a model of binge-like drinking ("drinking in the dark") that also included the use of lickometer circuits to evaluate the temporal pattern of intake as well as 2-bottle choice drinking in the home cage. In addition, EtOH (12% v/v) and sucrose (5% w/v) self-administration on fixed- and progressive-ratio schedules were also evaluated. A wide range of systemically administered oxytocin doses were tested (0 to 10 mg/kg) in these models. RESULTS Oxytocin (0, 0.3, 1, 3, or 10 mg/kg) dose dependently reduced EtOH consumption (maximal 45% reduction) in the binge drinking model, with lower effective doses having minimal effects on general locomotor activity. Oxytocin's effect was blocked by pretreatment with an oxytocin receptor antagonist, and the pattern of contacts (licks) at the EtOH bottle suggested a reduction in motivation to drink EtOH. Oxytocin decreased 2-bottle choice drinking without altering general fluid intake. Oxytocin also reduced operant responding for EtOH and sucrose in a dose-related manner. However, oxytocin decreased responding and motivation (breakpoint values) for EtOH at doses that did not alter responding for sucrose. CONCLUSIONS These results indicate that oxytocin reduces EtOH consumption in different models of self-administration. The effects are not likely due to a general sedative effect of the neuropeptide. Further, oxytocin reduces motivation for EtOH at doses that do not alter responding for a natural reward (sucrose). While some evidence supports a role for oxytocin receptors in mediating these effects, additional studies are needed to further elucidate underlying mechanisms. Nevertheless, these results support the therapeutic potential of oxytocin as a treatment for alcohol use disorder.
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Affiliation(s)
- Courtney E. King
- Charleston Alcohol Research Center, Departments of Psychiatry and Neuroscience, Medical University of South Carolina & VAMC, Charleston, SC 29425
| | - William C. Griffin
- Charleston Alcohol Research Center, Departments of Psychiatry and Neuroscience, Medical University of South Carolina & VAMC, Charleston, SC 29425
| | - Lauryn N. Luderman
- Charleston Alcohol Research Center, Departments of Psychiatry and Neuroscience, Medical University of South Carolina & VAMC, Charleston, SC 29425
| | - Malcolm M. Kates
- Charleston Alcohol Research Center, Departments of Psychiatry and Neuroscience, Medical University of South Carolina & VAMC, Charleston, SC 29425
| | - Jacqueline F. McGinty
- Charleston Alcohol Research Center, Departments of Psychiatry and Neuroscience, Medical University of South Carolina & VAMC, Charleston, SC 29425
| | - Howard C. Becker
- Charleston Alcohol Research Center, Departments of Psychiatry and Neuroscience, Medical University of South Carolina & VAMC, Charleston, SC 29425
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68
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Current findings on the role of oxytocin in the regulation of food intake. Physiol Behav 2017; 176:31-39. [PMID: 28284882 DOI: 10.1016/j.physbeh.2017.03.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/17/2017] [Accepted: 03/06/2017] [Indexed: 01/19/2023]
Abstract
In the face of the alarming prevalence of obesity and its associated metabolic impairments, it is of high basic and clinical interest to reach a complete understanding of the central nervous pathways that establish metabolic control. In recent years, the hypothalamic neuropeptide oxytocin, which is primarily known for its involvement in psychosocial processes and reproductive behavior, has received increasing attention as a modulator of metabolic function. Oxytocin administration to the brain of normal-weight animals, but also animals with diet-induced or genetically engineered obesity reduces food intake and body weight, and can also increase energy expenditure. Up to now, only a handful of studies in humans have investigated oxytocin's contribution to the regulation of eating behavior. Relying on the intranasal pathway of oxytocin administration, which is a non-invasive strategy to target central nervous oxytocin receptors, these experiments have yielded some promising first results. In normal-weight and obese individuals, intranasal oxytocin acutely limits meal intake and the consumption of palatable snacks. It is still unclear to which extent - or if at all - such metabolic effects of oxytocin in humans are conveyed or modulated by oxytocin's impact on cognitive processes, in particular on psychosocial function. We shortly summarize the current literature on oxytocin's involvement in food intake and metabolic control, ponder potential links to social and cognitive processes, and address future perspectives as well as limitations of oxytocin administration in experimental and clinical contexts.
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69
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De Melo VU, Saldanha RRM, Dos Santos CR, De Campos Cruz J, Lira VA, Santana-Filho VJ, Michelini LC. Ovarian Hormone Deprivation Reduces Oxytocin Expression in Paraventricular Nucleus Preautonomic Neurons and Correlates with Baroreflex Impairment in Rats. Front Physiol 2016; 7:461. [PMID: 27790154 PMCID: PMC5063006 DOI: 10.3389/fphys.2016.00461] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/26/2016] [Indexed: 11/24/2022] Open
Abstract
The prevalence of cardiovascular diseases including hypertension increases dramatically in women after menopause, however the mechanisms involved remain incompletely understood. Oxytocinergic (OTergic) neurons are largely present within the paraventricular nucleus of the hypothalamus (PVN). Several studies have shown that OTergic drive from PVN to brainstem increases baroreflex sensitivity and improves autonomic control of the circulation. Since preautonomic PVN neurons express different types of estrogen receptors, we hypothesize that ovarian hormone deprivation causes baroreflex impairment, autonomic imbalance and hypertension by negatively impacting OTergic drive and oxytocin levels in pre-autonomic neurons. Here, we assessed oxytocin gene and protein expression (qPCR and immunohistochemistry) within PVN subnuclei in sham-operated and ovariectomized Wistar rats. Conscious hemodynamic recordings were used to assess resting blood pressure and heart rate and the autonomic modulation of heart and vessels was estimated by power spectral analysis. We observed that the ovarian hormone deprivation in ovariectomized rats decreased baroreflex sensitivity, increased sympathetic and reduced vagal outflows to the heart and augmented the resting blood pressure. Of note, ovariectomized rats had reduced PVN oxytocin mRNA and protein expression in all pre-autonomic PVN subnuclei. Furthermore, reduced PVN oxytocin protein levels were positively correlated with decreased baroreflex sensitivity and negatively correlated with increased LF/HF ratio. These findings suggest that reduced oxytocin expression in OTergic neurons of the PVN contributes to the baroreflex dysfunction and autonomic dysregulation observed with ovarian hormone deprivation.
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Affiliation(s)
- Vitor U De Melo
- Department of Physiology, Federal University of SergipeSão Cristóvão, Brazil; Department of Health and Human Physiology, Obesity Research and Education Initiative, Fraternal Order of Eagles Diabetes Research Center, Abboud Cardiovascular Research Center, Pappajohn Biomedical Institute, University of IowaIowa, IA, USA
| | - Rayssa R M Saldanha
- Department of Physiology, Federal University of Sergipe São Cristóvão, Brazil
| | - Carla R Dos Santos
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo São Paulo, Brazil
| | | | - Vitor A Lira
- Department of Health and Human Physiology, Obesity Research and Education Initiative, Fraternal Order of Eagles Diabetes Research Center, Abboud Cardiovascular Research Center, Pappajohn Biomedical Institute, University of Iowa Iowa, IA, USA
| | | | - Lisete C Michelini
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo São Paulo, Brazil
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70
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Samson WK. Oxytocin redux. Am J Physiol Regul Integr Comp Physiol 2016; 311:R710-R713. [PMID: 27511282 DOI: 10.1152/ajpregu.00307.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 11/22/2022]
Affiliation(s)
- Willis K Samson
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, Saint Louis, Missouri
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71
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Central oxytocin receptor stimulation attenuates the orexigenic effects of butorphanol tartrate. Neuroreport 2016; 27:1012-7. [DOI: 10.1097/wnr.0000000000000647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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72
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Erdman SE, Poutahidis T. Microbes and Oxytocin: Benefits for Host Physiology and Behavior. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 131:91-126. [PMID: 27793228 DOI: 10.1016/bs.irn.2016.07.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is now understood that gut bacteria exert effects beyond the local boundaries of the gastrointestinal tract to include distant tissues and overall health. Prototype probiotic bacterium Lactobacillus reuteri has been found to upregulate hormone oxytocin and systemic immune responses to achieve a wide array of health benefits involving wound healing, mental health, metabolism, and myoskeletal maintenance. Together these display that the gut microbiome and host animal interact via immune-endocrine-brain signaling networks. Such findings provide novel therapeutic strategies to stimulate powerful homeostatic pathways and genetic programs, stemming from the coevolution of mammals and their microbiome.
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Affiliation(s)
- S E Erdman
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States; Aristotle University of Thessaloniki, Thessaloniki, Greece.
| | - T Poutahidis
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, United States; Aristotle University of Thessaloniki, Thessaloniki, Greece
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73
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Hewagalamulage SD, Clarke IJ, Rao A, Henry BA. Ewes With Divergent Cortisol Responses to ACTH Exhibit Functional Differences in the Hypothalamo-Pituitary-Adrenal (HPA) Axis. Endocrinology 2016; 157:3540-9. [PMID: 27414744 DOI: 10.1210/en.2016-1287] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Within any population, the cortisol response to ACTH covers a considerable range. High responders (HRs) exhibit a greater cortisol secretory response to stress or ACTH, compared with individuals classified as low cortisol responders (LRs). We administered ACTH (0.2 μg/kg, iv) to 160 female sheep and selected subpopulations of animals as LR and HR. In the present study, we aimed to characterize the hypothalamo-pituitary-adrenal axis in HR and LR and to identify factors that underlie the differing cortisol responses to ACTH. Hypothalami, pituitaries, and adrenals were collected from nonstressed HR and LR ewes. Expression of genes for CRH, arginine vasopressin (AVP), oxytocin, glucocorticoid receptor, and mineralocorticoid receptor were measured by in situ hybridization in the paraventricular nucleus of the hypothalamus, and proopiomelanocortin (POMC) gene expression was measured in the anterior pituitary. Expression of CRH, AVP, and POMC was higher in HR, with no differences in either glucocorticoid receptor or mineralocorticoid receptor expression. Oxytocin expression was greater in LR. In the adrenal gland, real-time PCR analysis indicated that expression of the ACTH receptor and a range of steroidogenic enzymes was similar in HR and LR. Adrenal weights, the cortex to medulla ratio and adrenal cortisol content were also similar in LR and HR. In conclusion, LR and HR display innate differences in the steady-state expression of CRH, AVP, oxytocin, and POMC, indicating that selection for cortisol responsiveness identifies distinct subpopulations that exhibit innate differences in the gene expression/function of hypothalamo-pituitary-adrenal axis markers.
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Affiliation(s)
- Sakda D Hewagalamulage
- Metabolic Disease and Obesity Program (S.D.H., B.A.H.) and Neuroscience Program (I.J.C., A.R.), Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria 3800, Australia
| | - Iain J Clarke
- Metabolic Disease and Obesity Program (S.D.H., B.A.H.) and Neuroscience Program (I.J.C., A.R.), Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria 3800, Australia
| | - Alexandra Rao
- Metabolic Disease and Obesity Program (S.D.H., B.A.H.) and Neuroscience Program (I.J.C., A.R.), Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria 3800, Australia
| | - Belinda A Henry
- Metabolic Disease and Obesity Program (S.D.H., B.A.H.) and Neuroscience Program (I.J.C., A.R.), Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria 3800, Australia
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74
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Pruimboom L, Reheis D. Intermittent drinking, oxytocin and human health. Med Hypotheses 2016; 92:80-3. [DOI: 10.1016/j.mehy.2016.04.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/26/2016] [Accepted: 04/26/2016] [Indexed: 02/08/2023]
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75
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Herisson FM, Waas JR, Fredriksson R, Schiöth HB, Levine AS, Olszewski PK. Oxytocin Acting in the Nucleus Accumbens Core Decreases Food Intake. J Neuroendocrinol 2016; 28. [PMID: 27114001 DOI: 10.1111/jne.12381] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 01/29/2016] [Accepted: 02/24/2016] [Indexed: 01/15/2023]
Abstract
Central oxytocin (OT) promotes feeding termination in response to homeostatic challenges, such as excessive stomach distension, salt loading and toxicity. OT has also been proposed to affect feeding reward by decreasing the consumption of palatable carbohydrates and sweet tastants. Because the OT receptor (OTR) is expressed in the nucleus accumbens core (AcbC) and shell (AcbSh), a site regulating diverse aspects of eating behaviour, we investigated whether OT acts there to affect appetite in rats. First, we examined whether direct AcbC and AcbSh OT injections affect hunger- and palatability-driven consumption. We found that only AcbC OT infusions decrease deprivation-induced chow intake and reduce the consumption of palatable sucrose and saccharin solutions in nondeprived animals. These effects were abolished by pretreatment with an OTR antagonist, L-368,899, injected in the same site. AcbC OT at an anorexigenic dose did not induce a conditioned taste aversion, which indicates that AcbC OT-driven anorexia is not caused by sickness/malaise. The appetite-specific effect of AcbC OT is supported by the real-time polymerase chain reaction analysis of OTR mRNA in the AcbC, which revealed that food deprivation elevates OTR mRNA expression, whereas saccharin solution intake decreases OTR transcript levels. We also used c-Fos immunohistochemistry as a marker of neuronal activation and found that AcbC OT injection increases activation of the AcbC itself, as well as of two feeding-related sites: the hypothalamic paraventricular and supraoptic nuclei. Finally, considering the fact that OT plays a significant role in social behaviour, we examined whether offering animals a meal in a social setting would modify their hypophagic response to AcbC OT injections. We found that a social context abolishes the anorexigenic effects of AcbC OT. We conclude that OT acting via the AcbC decreases food intake driven by hunger and reward in rats offered a meal in a nonsocial setting.
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Affiliation(s)
- F M Herisson
- Department of Biological Sciences, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | - J R Waas
- Department of Biological Sciences, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
| | - R Fredriksson
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - H B Schiöth
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - A S Levine
- Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA
| | - P K Olszewski
- Department of Biological Sciences, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand
- Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA
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76
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Olszewski PK, Klockars A, Levine AS. Oxytocin: A Conditional Anorexigen whose Effects on Appetite Depend on the Physiological, Behavioural and Social Contexts. J Neuroendocrinol 2016; 28. [PMID: 26918919 DOI: 10.1111/jne.12376] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 02/16/2016] [Accepted: 02/19/2016] [Indexed: 01/17/2023]
Abstract
Central oxytocin suppresses appetite. Neuronal activity and the release of oxytocin coincide with satiation, as well as with adverse events (e.g. hyperosmolality, toxicity or excessive stomach distension) that necessitate an immediate termination of eating behaviour. Oxytocin also decreases consumption driven by reward, especially as derived from ingesting carbohydrates and sweet tastants. This review summarises current knowledge of the role of oxytocin in food intake regulation and highlights a growing body of evidence showing that oxytocin is a conditional anorexigen [i.e. its effects on appetite differ significantly with respect to certain (patho)physiological, behavioural and social contexts].
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Affiliation(s)
- P K Olszewski
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - A Klockars
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - A S Levine
- Department of Food Science and Nutrition, University of Minnesota, St Paul, MN, USA
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77
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Blevins JE, Thompson BW, Anekonda VT, Ho JM, Graham JL, Roberts ZS, Hwang BH, Ogimoto K, Wolden-Hanson T, Nelson J, Kaiyala KJ, Havel PJ, Bales KL, Morton GJ, Schwartz MW, Baskin DG. Chronic CNS oxytocin signaling preferentially induces fat loss in high-fat diet-fed rats by enhancing satiety responses and increasing lipid utilization. Am J Physiol Regul Integr Comp Physiol 2016; 310:R640-58. [PMID: 26791828 DOI: 10.1152/ajpregu.00220.2015] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 01/14/2016] [Indexed: 12/30/2022]
Abstract
Based largely on a number of short-term administration studies, growing evidence suggests that central oxytocin is important in the regulation of energy balance. The goal of the current work is to determine whether long-term third ventricular (3V) infusion of oxytocin into the central nervous system (CNS) is effective for obesity prevention and/or treatment in rat models. We found that chronic 3V oxytocin infusion between 21 and 26 days by osmotic minipumps both reduced weight gain associated with the progression of high-fat diet (HFD)-induced obesity and elicited a sustained reduction of fat mass with no decrease of lean mass in rats with established diet-induced obesity. We further demonstrated that these chronic oxytocin effects result from 1) maintenance of energy expenditure at preintervention levels despite ongoing weight loss, 2) a reduction in respiratory quotient, consistent with increased fat oxidation, and 3) an enhanced satiety response to cholecystokinin-8 and associated decrease of meal size. These weight-reducing effects persisted for approximately 10 days after termination of 3V oxytocin administration and occurred independently of whether sucrose was added to the HFD. We conclude that long-term 3V administration of oxytocin to rats can both prevent and treat diet-induced obesity.
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Affiliation(s)
- James E Blevins
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington;
| | - Benjamin W Thompson
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Vishwanath T Anekonda
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Jacqueline M Ho
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - James L Graham
- Department of Nutrition and Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California; and
| | - Zachary S Roberts
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Bang H Hwang
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Kayoko Ogimoto
- Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, Washington
| | - Tami Wolden-Hanson
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington
| | - Jarrell Nelson
- Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, Washington
| | - Karl J Kaiyala
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, Washington
| | - Peter J Havel
- Department of Nutrition and Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California; and
| | - Karen L Bales
- Department of Psychology, University of California, Davis, California
| | - Gregory J Morton
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington; Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, Washington
| | - Michael W Schwartz
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington; Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, Washington
| | - Denis G Baskin
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
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78
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Otero-García M, Agustín-Pavón C, Lanuza E, Martínez-García F. Distribution of oxytocin and co-localization with arginine vasopressin in the brain of mice. Brain Struct Funct 2015; 221:3445-73. [PMID: 26388166 DOI: 10.1007/s00429-015-1111-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/09/2015] [Indexed: 12/19/2022]
Abstract
Oxytocin (OT) and vasopressin (AVP) play a major role in social behaviours. Mice have become the species of choice for neurobiology of social behaviour due to identification of mouse pheromones and the advantage of genetically modified mice. However, neuroanatomical data on nonapeptidergic systems in mice are fragmentary, especially concerning the central distribution of OT. Therefore, we analyse the immunoreactivity for OT and its neurophysin in the brain of male and female mice (strain CD1). Further, we combine immunofluorescent detection of OT and AVP to locate cells co-expressing both peptides and their putative axonal processes. The results indicate that OT is present in cells of the neurosecretory paraventricular (Pa) and supraoptic hypothalamic nuclei (SON). From the anterior SON, OTergic cells extend into the medial amygdala, where a sparse cell population occupies its ventral anterior and posterior divisions. Co-expression of OT and AVP in these nuclei is rare. Moreover, a remarkable OTergic cell group is found near the ventral bed nucleus of the stria terminalis (BST), distributed between the anterodorsal preoptic nucleus and the nucleus of anterior commissure (ADP/AC). This cell group, the rostral edge of the Pa and the periventricular hypothalamus display frequent OT + AVP double labelling, with a general dominance of OT over AVP immunoreactivity. Fibres with similar immunoreactivity profile innervate the accumbens shell and core, central amygdala and portions of the intervening BST. These data, together with data in the literature on rats, suggest that the projections of ADP/AC nonapeptidergic cells onto these brain centres could promote pup-motivated behaviours and inhibit pup avoidance during motherhood.
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Affiliation(s)
- Marcos Otero-García
- Departaments de Biologia Cel·lular i de Biologia Funcional, Facultat de Ciències Biològiques, Universitat de València, València, Spain
| | - Carmen Agustín-Pavón
- Lab. of Functional Neuroanatomy (NeuroFun), Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain
| | - Enrique Lanuza
- Departaments de Biologia Cel·lular i de Biologia Funcional, Facultat de Ciències Biològiques, Universitat de València, València, Spain
| | - Fernando Martínez-García
- Lab. of Functional Neuroanatomy (NeuroFun), Unitat Predepartamental de Medicina, Facultat de Ciències de la Salut, Universitat Jaume I, Av. de Vicent Sos Baynat, s/n, 12071, Castelló de la Plana, Spain.
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79
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Blevins JE, Baskin DG. Translational and therapeutic potential of oxytocin as an anti-obesity strategy: Insights from rodents, nonhuman primates and humans. Physiol Behav 2015; 152:438-49. [PMID: 26013577 DOI: 10.1016/j.physbeh.2015.05.023] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 12/15/2022]
Abstract
The fact that more than 78 million adults in the US are considered overweight or obese highlights the need to develop new, effective strategies to treat obesity and its associated complications, including type 2 diabetes, kidney disease and cardiovascular disease. While the neurohypophyseal peptide oxytocin (OT) is well recognized for its peripheral effects to stimulate uterine contraction during parturition and milk ejection during lactation, release of OT within the brain is implicated in prosocial behaviors and in the regulation of energy balance. Previous findings indicate that chronic administration of OT decreases food intake and weight gain or elicits weight loss in diet-induced obese (DIO) mice and rats. Furthermore, chronic systemic treatment with OT largely reproduces the effects of central administration to reduce weight gain in DIO and genetically obese rodents at doses that do not appear to result in tolerance. These findings have now been recently extended to more translational models of obesity showing that chronic subcutaneous or intranasal OT treatment is sufficient to elicit body weight loss in DIO nonhuman primates and pre-diabetic obese humans. This review assesses the potential use of OT as a therapeutic strategy for treatment of obesity in rodents, nonhuman primates, and humans, and identifies potential mechanisms that mediate this effect.
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Affiliation(s)
- James E Blevins
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - Denis G Baskin
- VA Puget Sound Health Care System, Office of Research and Development, Medical Research Service, Department of Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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80
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Lawson EA, Marengi DA, DeSanti RL, Holmes TM, Schoenfeld DA, Tolley CJ. Oxytocin reduces caloric intake in men. Obesity (Silver Spring) 2015; 23:950-6. [PMID: 25865294 PMCID: PMC4414748 DOI: 10.1002/oby.21069] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/24/2015] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Preclinical studies indicate that oxytocin is anorexigenic and has beneficial metabolic effects. Oxytocin effects on nutrition and metabolism in humans are not well defined. It was hypothesized that oxytocin would reduce caloric intake and appetite and alter levels of appetite-regulating hormones. Metabolic effects of oxytocin were also explored. METHODS A randomized, placebo-controlled crossover study of single-dose intranasal oxytocin (24 IU) in 25 fasting healthy men was performed. After oxytocin/placebo, subjects selected breakfast from a menu and were given double portions. Caloric content of food consumed was measured. Visual analog scales were used to assess appetite, and blood was drawn for appetite-regulating hormones, insulin, and glucose before and after oxytocin/placebo. Indirect calorimetry assessed resting energy expenditure (REE) and substrate utilization. RESULTS Oxytocin reduced caloric intake with a preferential effect on fat intake and increased levels of the anorexigenic hormone cholecystokinin without affecting appetite or other appetite-regulating hormones. There was no effect of oxytocin on REE. Oxytocin resulted in a shift from carbohydrate to fat utilization and improved insulin sensitivity. CONCLUSIONS Intranasal oxytocin reduces caloric intake and has beneficial metabolic effects in men without concerning side effects. The efficacy and safety of sustained oxytocin administration in the treatment of obesity warrants investigation.
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Affiliation(s)
- Elizabeth A. Lawson
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - Dean A. Marengi
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - Rebecca L. DeSanti
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - Tara M. Holmes
- Harvard Catalyst Clinical Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - David A. Schoenfeld
- Department of Biostatistics, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
| | - Christiane J. Tolley
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114
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81
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Ong ZY, Alhadeff AL, Grill HJ. Medial nucleus tractus solitarius oxytocin receptor signaling and food intake control: the role of gastrointestinal satiation signal processing. Am J Physiol Regul Integr Comp Physiol 2015; 308:R800-6. [PMID: 25740340 DOI: 10.1152/ajpregu.00534.2014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 02/24/2015] [Indexed: 12/23/2022]
Abstract
Central oxytocin (OT) administration reduces food intake and its effects are mediated, in part, by hindbrain oxytocin receptor (OT-R) signaling. The neural substrate and mechanisms mediating the intake inhibitory effects of hindbrain OT-R signaling are undefined. We examined the hypothesis that hindbrain OT-R-mediated feeding inhibition results from an interaction between medial nucleus tractus solitarius (mNTS) OT-R signaling and the processing of gastrointestinal (GI) satiation signals by neurons of the mNTS. Here, we demonstrated that mNTS or fourth ventricle (4V) microinjections of OT in rats reduced chow intake in a dose-dependent manner. To examine whether the intake suppressive effects of mNTS OT-R signaling is mediated by GI signal processing, rats were injected with OT to the 4V (1 μg) or mNTS (0.3 μg), followed by self-ingestion of a nutrient preload, where either treatment was designed to be without effect on chow intake. Results showed that the combination of mNTS OT-R signaling and GI signaling processing by preload ingestion reduced chow intake significantly and to a greater extent than either stimulus alone. Using enzyme immunoassay, endogenous OT content in mNTS-enriched dorsal vagal complex (DVC) in response to ingestion of nutrient preload was measured. Results revealed that preload ingestion significantly elevated endogenous DVC OT content. Taken together, these findings provide evidence that mNTS neurons are a site of action for hindbrain OT-R signaling in food intake control and that the intake inhibitory effects of hindbrain mNTS OT-R signaling are mediated by interactions with GI satiation signal processing by mNTS neurons.
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Affiliation(s)
- Zhi Yi Ong
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Amber L Alhadeff
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Harvey J Grill
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania
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82
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Olszewski PK, Allen K, Levine AS. Effect of oxytocin receptor blockade on appetite for sugar is modified by social context. Appetite 2015; 86:81-7. [DOI: 10.1016/j.appet.2014.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 09/23/2014] [Accepted: 10/13/2014] [Indexed: 01/28/2023]
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83
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Zhou L, Ghee SM, See RE, Reichel CM. Oxytocin differentially affects sucrose taking and seeking in male and female rats. Behav Brain Res 2015; 283:184-90. [PMID: 25647756 PMCID: PMC4387851 DOI: 10.1016/j.bbr.2015.01.050] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/17/2014] [Accepted: 01/23/2015] [Indexed: 02/08/2023]
Abstract
Oxytocin has a modulatory role in natural and drug reward processes. While the role of oxytocin in pair bonding and reproduction has been extensively studied, sex differences in conditioned and unconditioned behavioral responses to oxytocin treatment have not been fully characterized. Here, we determined whether male and female rats would show similar dose response curves in response to acute oxytocin on measures of locomotor activity, sucrose seeking, and sucrose intake. Male and freely cycling female rats received vehicle or oxytocin (0.1, 0.3, 1, 3 mg/kg, IP) injections before behavioral tests designed to assess general motor activity, as well as sucrose self-administration and seeking. Lower doses of oxytocin decreased motor activity in a novel environment in females relative to males. Likewise, lower doses of oxytocin in females decreased responding for sucrose during maintenance of sucrose self-administration and reinstatement to sucrose-conditioned cues. However, sucrose seeking in response to a sucrose prime was only decreased by the highest oxytocin dose in both sexes. In general, oxytocin had similar effects in both sexes. However, females were more sensitive to lower doses of oxytocin than males. These findings are consistent with the notion that oxytocin regulates many of the same behaviors in males and females, but that the effects are typically more profound in females. Therapeutic use of oxytocin should include sex as a factor in determining dose regimens.
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Affiliation(s)
- Luyi Zhou
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Shannon M Ghee
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Ronald E See
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Carmela M Reichel
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA.
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84
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Klockars A, Levine AS, Olszewski PK. Central oxytocin and food intake: focus on macronutrient-driven reward. Front Endocrinol (Lausanne) 2015; 6:65. [PMID: 25972841 PMCID: PMC4412129 DOI: 10.3389/fendo.2015.00065] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/13/2015] [Indexed: 11/17/2022] Open
Abstract
Centrally acting oxytocin (OT) is known to terminate food consumption in response to excessive stomach distension, increase in salt loading, and presence of toxins. Hypothalamic-hindbrain OT pathways facilitate these aspects of OT-induced hypophagia. However, recent discoveries have implicated OT in modifications of feeding via reward circuits: OT has been found to differentially affect consumption of individual macronutrients in choice and no-choice paradigms. In this mini-review, we focus on presenting and interpreting evidence that defines OT as a key component of mechanisms that reduce eating for pleasure and shape macronutrient preferences. We also provide remarks on challenges in integrating the knowledge on physiological and pathophysiological states in which both OT activity and macronutrient preferences are affected.
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Affiliation(s)
- Anica Klockars
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - Allen Stuart Levine
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Pawel Karol Olszewski
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
- *Correspondence: Pawel Karol Olszewski, Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand,
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85
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Blevins JE, Graham JL, Morton GJ, Bales KL, Schwartz MW, Baskin DG, Havel PJ. Chronic oxytocin administration inhibits food intake, increases energy expenditure, and produces weight loss in fructose-fed obese rhesus monkeys. Am J Physiol Regul Integr Comp Physiol 2014; 308:R431-8. [PMID: 25540103 DOI: 10.1152/ajpregu.00441.2014] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite compelling evidence that oxytocin (OT) is effective in reducing body weight (BW) in diet-induced obese (DIO) rodents, studies of the effects of OT in humans and rhesus monkeys have primarily focused on noningestive behaviors. The goal of this study was to translate findings in DIO rodents to a preclinical translational model of DIO. We tested the hypothesis that increased OT signaling would reduce BW in DIO rhesus monkeys by inhibiting food intake and increasing energy expenditure (EE). Male DIO rhesus monkeys from the California National Primate Research Center were adapted to a 12-h fast and maintained on chow and a daily 15% fructose-sweetened beverage. Monkeys received 2× daily subcutaneous vehicle injections over 1 wk. We subsequently identified doses of OT (0.2 and 0.4 mg/kg) that reduced food intake and BW in the absence of nausea or diarrhea. Chronic administration of OT for 4 wk (0.2 mg/kg for 2 wk; 0.4 mg/kg for 2 wk) reduced BW relative to vehicle by 3.3 ± 0.4% (≈0.6 kg; P < 0.05). Moreover, the low dose of OT suppressed 12-h chow intake by 26 ± 7% (P < 0.05). The higher dose of OT reduced 12-h chow intake by 27 ± 5% (P < 0.05) and 8-h fructose-sweetened beverage intake by 18 ± 8% (P < 0.05). OT increased EE during the dark cycle by 14 ± 3% (P < 0.05) and was associated with elevations of free fatty acids and glycerol and reductions in triglycerides suggesting increased lipolysis. Together, these data suggest that OT reduces BW in DIO rhesus monkeys through decreased food intake as well as increased EE and lipolysis.
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Affiliation(s)
- James E Blevins
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington;
| | - James L Graham
- Department of Nutrition and Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California; and
| | - Gregory J Morton
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington; Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, Washington
| | - Karen L Bales
- Department of Psychology, University of California, Davis, California
| | - Michael W Schwartz
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington; Diabetes and Obesity Center of Excellence, University of Washington School of Medicine, Seattle, Washington
| | - Denis G Baskin
- Veterans Affairs Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, Washington; Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - Peter J Havel
- Department of Nutrition and Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California; and
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86
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Zhou L, Sun WL, Young AB, Lee K, McGinty JF, See RE. Oxytocin reduces cocaine seeking and reverses chronic cocaine-induced changes in glutamate receptor function. Int J Neuropsychopharmacol 2014; 18:pyu009. [PMID: 25539504 PMCID: PMC4368863 DOI: 10.1093/ijnp/pyu009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Oxytocin, a neurohypophyseal neuropeptide, is a potential mediator and regulator of drug addiction. However, the cellular mechanisms of oxytocin in drug seeking remain unknown. METHODS In the present study, we used a self-administration/reinstatement model to study the effects of oxytocin on cocaine seeking and its potential interaction with glutamate function at the receptor level. RESULTS Systemic oxytocin dose-dependently reduced cocaine self-administration during various schedules of reinforcement, including fixed ratio 1, fixed ratio 5, and progressive ratio. Oxytocin also attenuated reinstatement to cocaine seeking induced by cocaine prime or conditioned cues. Western-blot analysis indicated that oxytocin increased phosphorylation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor GluA1 subunit at the Ser 845 site with or without accompanying increases in phosphorylation of extracellular signal-regulated kinase, in several brain regions, including the prefrontal cortex, bed nucleus of the stria terminalis, amygdala, and dorsal hippocampus. Immunoprecipitation of oxytocin receptor and GluA1 subunit receptors further demonstrated a physical interaction between these 2 receptors, although the interaction was not influenced by chronic cocaine or oxytocin treatment. Oxytocin also attenuated sucrose seeking in a GluA1- or extracellular-signal-regulated kinase-independent manner. CONCLUSIONS These findings suggest that oxytocin mediates cocaine seeking through interacting with glutamate receptor systems via second messenger cascades in mesocorticolimbic regions.
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Affiliation(s)
- Luyi Zhou
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (Drs Zhou, Sun, Young, Lee, McGinty, and See)
| | - Wei-Lun Sun
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (Drs Zhou, Sun, Young, Lee, McGinty, and See)
| | - Amy B Young
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (Drs Zhou, Sun, Young, Lee, McGinty, and See)
| | - Kunhee Lee
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (Drs Zhou, Sun, Young, Lee, McGinty, and See)
| | - Jacqueline F McGinty
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (Drs Zhou, Sun, Young, Lee, McGinty, and See)
| | - Ronald E See
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina (Drs Zhou, Sun, Young, Lee, McGinty, and See).
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87
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Oxytocinergic circuit from paraventricular and supraoptic nuclei to arcuate POMC neurons in hypothalamus. FEBS Lett 2014; 588:4404-12. [DOI: 10.1016/j.febslet.2014.10.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 10/07/2014] [Accepted: 10/09/2014] [Indexed: 10/24/2022]
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88
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Williams DL. Neural integration of satiation and food reward: role of GLP-1 and orexin pathways. Physiol Behav 2014; 136:194-9. [PMID: 24650552 PMCID: PMC4167985 DOI: 10.1016/j.physbeh.2014.03.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/23/2014] [Accepted: 03/10/2014] [Indexed: 02/07/2023]
Abstract
Central nervous system control of food intake involves detecting, integrating and responding to diverse internal and external signals. For maintenance of energy homeostasis, the brain uses long-term signals of metabolic status and short-term signals related to the nutrient content of individual meals. Feeding is also clearly influenced by hedonic, reward-related factors: palatability, motivation, and learned associations and cues that predict the availability of food. Different neural circuits have been proposed to mediate these homeostatic and hedonic aspects of eating. This review describes research on neural pathways that appear to be involved in both, integrating gastrointestinal satiation signaling with food reward. First, the glucagon-like peptide 1 projections from the nucleus of the solitary tract to the nucleus accumbens and ventral tegmental area are discussed as a mechanism through which meal-related gut signals may influence palatability, motivation for food, and meal size. Second, the orexin projection from lateral hypothalamus to the nucleus of the solitary tract and area postrema is discussed as a mechanism through which cues that predict rewarding food may act to increase motivation for food and also to suppress satiation. Additional potential integrative sites and pathways are also briefly discussed. Based on these findings, it is suggested that the brain circuitry involved in energy homeostasis and the circuitry mediating food reward are, in fact, overlapping and far less distinct than previously considered.
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Affiliation(s)
- Diana L Williams
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, USA.
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89
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Veening JG, de Jong TR, Waldinger MD, Korte SM, Olivier B. The role of oxytocin in male and female reproductive behavior. Eur J Pharmacol 2014; 753:209-28. [PMID: 25088178 DOI: 10.1016/j.ejphar.2014.07.045] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/30/2014] [Accepted: 07/24/2014] [Indexed: 01/01/2023]
Abstract
Oxytocin (OT) is a nonapeptide with an impressive variety of physiological functions. Among them, the 'prosocial' effects have been discussed in several recent reviews, but the direct effects on male and female sexual behavior did receive much less attention so far. As our contribution to honor the lifelong interest of Berend Olivier in the control mechanisms of sexual behavior, we decided to explore the role of OT in the present review. In the successive sections, some physiological mechanisms and the 'pair-bonding' effects of OT will be discussed, followed by sections about desire, female appetitive and copulatory behavior, including lordosis and orgasm. At the male side, the effects on erection and ejaculation are reviewed, followed by a section about 'premature ejaculation' and a possible role of OT in its treatment. In addition to OT, serotonin receives some attention as one of the main mechanisms controlling the effects of OT. In the succeeding sections, the importance of OT for 'the fruits of labor' is discussed, as it plays an important role in both maternal and paternal behavior. Finally, we pay attention to an intriguing brain area, the ventrolateral part of the ventromedial hypothalamic nucleus (VMHvl), apparently functioning in both sexual and aggressive behavior, which are at first view completely opposite behavioral systems.
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Affiliation(s)
- J G Veening
- Department of Psychopharmacology, Division of Pharmacology, University of Utrecht, Utrecht, The Netherlands; Department of Anatomy, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - T R de Jong
- Department of Behavioral and Molecular Neurobiology, University of Regensburg, 93053 Regensburg, Germany
| | - M D Waldinger
- Department of Psychopharmacology, Division of Pharmacology, University of Utrecht, Utrecht, The Netherlands
| | - S M Korte
- Department of Psychopharmacology, Division of Pharmacology, University of Utrecht, Utrecht, The Netherlands
| | - B Olivier
- Department of Psychopharmacology, Division of Pharmacology, University of Utrecht, Utrecht, The Netherlands
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90
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Noble EE, Billington CJ, Kotz CM, Wang C. Oxytocin in the ventromedial hypothalamic nucleus reduces feeding and acutely increases energy expenditure. Am J Physiol Regul Integr Comp Physiol 2014; 307:R737-45. [PMID: 24990860 DOI: 10.1152/ajpregu.00118.2014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Central oxytocin reduces food intake and increases energy expenditure. The ventromedial hypothalamic nucleus (VMN) is associated with energy balance and contains a high density of oxytocin receptors. We hypothesized that oxytocin in the VMN is a negative regulator of energy balance acting to reduce feeding and increase energy expenditure. To test this idea, oxytocin or vehicle was injected directly into the VMN of Sprague-Dawley rats during fasted and nonfasted conditions. Energy expenditure (via indirect calorimetry) and spontaneous physical activity (SPA) were recorded simultaneously. Animals were also exposed to a conditioned taste aversion test, to determine whether oxytocin's effects on food intake were associated with malaise. When food was available during testing, oxytocin-induced elevations in energy expenditure lasted for 1 h, after which overall energy expenditure was reduced. In the absence of food during the testing period, oxytocin similarly increased energy expenditure during the first hour, but differences in 12-h energy expenditure were eliminated, implying that the differences may have been due to the thermic effects of feeding (digestion, absorption, and metabolic processing). Oxytocin acutely elevated SPA and reduced feeding at doses that did not cause a conditioned taste aversion during both the fed and fasted states. Together, these data suggest that oxytocin in the VMN promotes satiety and acutely elevates energy expenditure and SPA and implicates the VMN as a relevant site for the antiobesity effects of oxytocin.
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Affiliation(s)
- Emily E Noble
- Department of Food Science and Nutrition, University of Minnesota, Saint Paul, Minnesota; Minnesota Obesity Center, University of Minnesota, Saint Paul, Minnesota; and
| | - Charles J Billington
- Department of Food Science and Nutrition, University of Minnesota, Saint Paul, Minnesota; Department of Medicine, University of Minnesota, Saint Paul, Minnesota; Minnesota Obesity Center, University of Minnesota, Saint Paul, Minnesota; and Minneapolis VA Health Care System, Minneapolis, Minnesota
| | - Catherine M Kotz
- Department of Food Science and Nutrition, University of Minnesota, Saint Paul, Minnesota; Department of Neuroscience, University of Minnesota, Saint Paul, Minnesota; Minnesota Obesity Center, University of Minnesota, Saint Paul, Minnesota; and Minneapolis VA Health Care System, Minneapolis, Minnesota
| | - ChuanFeng Wang
- Department of Food Science and Nutrition, University of Minnesota, Saint Paul, Minnesota; Minnesota Obesity Center, University of Minnesota, Saint Paul, Minnesota; and Minneapolis VA Health Care System, Minneapolis, Minnesota
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Asevedo E, Rizzo LB, Gadelha A, Mansur RB, Ota VK, Berberian AA, Scarpato BS, Teixeira AL, Bressan RA, Brietzke E. Peripheral interleukin-2 level is associated with negative symptoms and cognitive performance in schizophrenia. Physiol Behav 2014; 129:194-8. [PMID: 24576679 DOI: 10.1016/j.physbeh.2014.02.032] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 10/07/2013] [Accepted: 02/12/2014] [Indexed: 01/13/2023]
Abstract
Although several studies have pointed to a possible role of interleukin 2 (IL-2) in schizophrenia (SZ), association between IL-2 and the different groups of symptoms has not been explored. The objective of this study was to investigate a possible correlation of peripheral IL-2 levels with symptoms and cognitive performance in patients with SZ. In addition, we compared the plasma levels of IL-2 between patients with SZ and healthy controls. Twenty-nine chronically medicated outpatients with SZ according to DSM-IV were compared with twenty-six healthy controls. The patients were evaluated with the Positive and Negative Syndrome Scale (PANSS), the Calgary Depression Scale for Schizophrenia (CDSS), the Clinical Global Impression (CGI) and the Global Assessment of Functioning (GAF). All the participants had blood collected into EDTA tubes by venipuncture between 9:00 and 10:00AM. Plasma concentrations of IL-2 were determined by cytometric bead array. A computerized neuropsychological battery assessed verbal learning, verbal fluency, working memory, set shifting, executive function, inhibition and intelligence. Patients with SZ had lower levels of IL-2 than healthy controls (p<0.001). In the SZ group, IL-2 levels were positively correlated with scores in the digit span test (rho=0.416, P=0.025) and intelligence (rho=0.464, P=0.011). We also found a negative correlation between IL-2 and total score in the negative subscale of PANSS (rho=-0.447, p=0.015). Our findings suggest that IL-2 may be involved in the mechanisms related to cognitive deterioration and negative symptomatology in schizophrenia.
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Affiliation(s)
- Elson Asevedo
- Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Lucas B Rizzo
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Ary Gadelha
- Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Rodrigo B Mansur
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Vanessa K Ota
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Arthur A Berberian
- Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Bruno S Scarpato
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Antônio L Teixeira
- Translational Psychoneuroimmunology Group, Federal University of Minas Gerais, Avenida Antonio Carlos, 6627, Pampulha, Belo Horizonte MG, CEP 31270-901, Brazil.
| | - Rodrigo A Bressan
- Schizophrenia Program (PROESQ), Department of Psychiatry, Federal University of São Paulo, Rua Machado Bittencourt, 222, São Paulo, SP, CEP 04044-000, Brazil; Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
| | - Elisa Brietzke
- Interdisciplinary Laboratory of Clinical Neurosciences (LINC), Department of Psychiatry, Federal University of São Paulo, Rua Pedro de Toledo, 669, Edifício de Pesquisas II, third floor, São Paulo SP, CEP 04039-032, Brazil.
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Abstract
Obesity and its associated metabolic disorders are growing health concerns in the US and worldwide. In the US alone, more than two-thirds of the adult population is classified as either overweight or obese [1], highlighting the need to develop new, effective treatments for these conditions. Whereas the hormone oxytocin is well known for its peripheral effects on uterine contraction during parturition and milk ejection during lactation, release of oxytocin from somatodendrites and axonal terminals within the central nervous system (CNS) is implicated in both the formation of prosocial behaviors and in the control of energy balance. Recent findings demonstrate that chronic administration of oxytocin reduces food intake and body weight in diet-induced obese (DIO) and genetically obese rodents with impaired or defective leptin signaling. Importantly, chronic systemic administration of oxytocin out to 6 weeks recapitulates the effects of central administration on body weight loss in DIO rodents at doses that do not result in the development of tolerance. Furthermore, these effects are coupled with induction of Fos (a marker of neuronal activation) in hindbrain areas (e.g. dorsal vagal complex (DVC)) linked to the control of meal size and forebrain areas (e.g. hypothalamus, amygdala) linked to the regulation of food intake and body weight. This review assesses the potential central and peripheral targets by which oxytocin may inhibit body weight gain, its regulation by anorexigenic and orexigenic signals, and its potential use as a therapy that can circumvent leptin resistance and reverse the behavioral and metabolic abnormalities associated with DIO and genetically obese models.
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Affiliation(s)
- James E Blevins
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, 98108, USA,
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93
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Tang Y, Chen Z, Tao H, Li C, Zhang X, Tang A, Liu Y. Oxytocin activation of neurons in ventral tegmental area and interfascicular nucleus of mouse midbrain. Neuropharmacology 2013; 77:277-84. [PMID: 24148809 DOI: 10.1016/j.neuropharm.2013.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 10/26/2022]
Abstract
Oxytocin (OT) was reported to affect cognitive and emotional behavior by action in ventral tegmental area (VTA) and other brain areas. However, it is still unclear how OT activates VTA and related midline nucleus. Here, using patch-clamp recording, we studied the effects of OT on neuron activity in VTA and interfascicular nucleus (IF). OT dose-dependently and selectively excited small neurons located in medial VTA and the majority of IF neurons but not large neurons in lateral VTA. We found the hyperpolarization-activated current (I(h)) and the membrane capacitance of OT-sensitive neuron were significantly smaller than those of OT-insensitive neurons. The action potential width of OT-sensitive neurons was about half that of OT-insensitive neurons. The OT effect was blocked by the OT receptor antagonist atosiban and WAY-267464 but not by tetrodotoxin, suggesting a direct postsynaptic activation of OT receptors. In addition, the phospholipase C (PLC) inhibitor U73122 antagonized the depolarization by OT. Both the nonselective cation channel (NSCC) antagonist SKF96365 and the Na(+)-Ca(2+) exchanger (NCX) blocker SN-6 attenuated OT effects. These results suggested that the PLC signaling pathway coupling to NSCC and NCX contributes to the OT-mediated activation of neurons in medial VTA and IF. Taken together, our results indicate OT directly acted on medial VTA and especially IF neurons to activate NSCC and NCX via PLC. The direct activation by OT of midbrain neurons may be one mechanism underlying OT effects on social behavior.
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Affiliation(s)
- Yamei Tang
- Department of Laboratory, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Zhiheng Chen
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Huai Tao
- Department of Biochemistry and Molecular Biology, Hunan University of Chinese Medicine, Changsha 410208, China
| | - Cunyan Li
- Department of Laboratory, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Xianghui Zhang
- Mental Health Institute, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Road, Changsha 410011, China
| | - Aiguo Tang
- Department of Laboratory, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Yong Liu
- Mental Health Institute, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Road, Changsha 410011, China.
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Ott V, Finlayson G, Lehnert H, Heitmann B, Heinrichs M, Born J, Hallschmid M. Oxytocin reduces reward-driven food intake in humans. Diabetes 2013; 62:3418-25. [PMID: 23835346 PMCID: PMC3781467 DOI: 10.2337/db13-0663] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Experiments in animals suggest that the neuropeptide oxytocin acts as an anorexigenic signal in the central nervous control of food intake. In humans, however, research has almost exclusively focused on the involvement of oxytocin in the regulation of social behavior. We investigated the effect of intranasal oxytocin on ingestion and metabolic function in healthy men. Food intake in the fasted state was examined 45 min after neuropeptide administration, followed by the assessment of olfaction and reward-driven snack intake in the absence of hunger. Energy expenditure was registered by indirect calorimetry, and blood was repeatedly sampled to determine concentrations of blood glucose and hormones. Oxytocin markedly reduced snack consumption, restraining, in particular, the intake of chocolate cookies by 25%. Oxytocin, moreover, attenuated basal and postprandial levels of adrenocorticotropic hormone and cortisol and curbed the meal-related rise in plasma glucose. Energy expenditure and hunger-driven food intake as well as olfactory function were not affected. Our results indicate that oxytocin, beyond its role in social bonding, regulates nonhomeostatic, reward-related energy intake, hypothalamic-pituitary-adrenal axis activity, and the glucoregulatory response to food intake in humans. These effects can be assumed to converge with the psychosocial function of oxytocin and imply possible applications in the treatment of metabolic disorders.
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Affiliation(s)
- Volker Ott
- Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany
| | - Graham Finlayson
- Institute of Psychological Sciences, University of Leeds, Leeds, U.K
| | - Hendrik Lehnert
- Department of Internal Medicine I, University of Lübeck, Lübeck, Germany
| | - Birte Heitmann
- Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany
| | - Markus Heinrichs
- Laboratory for Biological and Personality Psychology, Department of Psychology, University of Freiburg, Freiburg, Germany
- Freiburg Brain Imaging Center, University Medical Center, University of Freiburg, Freiburg, Germany
| | - Jan Born
- Department of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen (Paul Langerhans Institute Tübingen), Tübingen, Germany
| | - Manfred Hallschmid
- Department of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen (Paul Langerhans Institute Tübingen), Tübingen, Germany
- Corresponding author: Manfred Hallschmid,
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